1. Field of the Invention
This invention pertains to the field of safes. More particularly, it pertains to the field of large and small safes that are made of inner and outer safe containers maintained in spaced-apart concentricity by the use of a curable compound inserted between the containers that hardens to become a very formidable barrier. This invention pertains to a special type of safe and method of making it where the problem of distortion, caused by welding together parts of the containers, and deformation caused by the exothermic reaction of the curable compound, are eliminated.
2. Description of the Prior Art
Safes have been around for hundreds of years. The propensity of humans to steal what does not belong to them has been recognized in every part of the world and containers made safe against such theft have been a part of our society since the early days of civilization.
There are many different types and designs of manufactured safes. The particular safe with which this invention is involved comprises an inner box or container made of metal housed inside an outer box or container of metal wherein the space between the boxes is filled with a curable material having the consistency and strength of concrete. The general structure of safes of this type involves the inner metal box located inside an outer metal box that is accessible through a front opening covered by a lockable safe door.
During construction, an opening is formed in the outer metal box through which the concrete-like material is charged in between the boxes and allowed to cure. A plate or cover is then welded over the opening to complete the structure. A standard safe door, containing a moveable handle, a combination or other type of lockable mechanism, and moveable locking rods is hung by hinges over the opening into the interior of the two containers.
The two-container safes of the prior art are generally joined together in concentric alignment by metal strips located in the space between the walls and are welded to each container and then welded together. The containers are then subject to working to straighten out the warpage that is commonly encountered with welded materials. A common problem encountered in the manufacture of these "two-box" safes is that the containers and other accessories warp and become disfigured when subject to heat from the welding operation. Further, when the concrete-like material, filled in the space between the containers, begins to cure, the exotherm or heat generated in the chemical reaction also causes warpage in the metal against which the material is contacted.
It is well-known that heating one particular place on a complex metal configuration causes local warpage of the metal to the point that the whole structure may be pulled out of shape. When this occurs, it requires remedial work, i.e., heating and bending the metal parts back into alignment. With safes, such remedial work is necessary so the heavy safe door operates properly (opens and closes easily) and that the overall design retains its aesthetic appearance with 90.degree. corners and parallel sides. This extra work to straighten and realign the inner and outer containers constitutes a cost of manufacture that not only raises the price of this kind of safe but also slows the manufacturing process of safes and delays them in getting to the buyer.
The material charged into the empty space between the inner and outer boxes undergoes an exothermic reaction during curing. The heat from this reaction often is so great as to further warp the already warped parts of the safe.